Though present in natural settings at minute quantities, ethylene oxide was first synthesized in a laboratory setting in 1859 by Alsatian chemist Charles-Adolphe Wurtz using the so-called “chlorohydrin” process. However, the usefulness of ethylene oxide as an industrial chemical was not fully understood in Wurtz's time. Industrial production of ethylene oxide using the chlorohydrin process did not begin until the eve of the First World War with the rapid increase in demand for ethylene glycol (of which ethylene oxide is an intermediate) as an antifreeze for use in the rapidly-growing automotive market. Even then, the chlorohydrin process produced ethylene oxide in relatively small quantities and was highly uneconomical.
The chlorohydrin process was eventually supplanted by another process, the direct catalytic oxidation of ethylene with oxygen, the result of a second breakthrough in ethylene oxide synthesis, discovered in 1931 by French chemist Theodore Lefort. Lefort used a solid silver catalyst with a gas phase feed that included ethylene and utilized air as a source of oxygen.
In the eighty years since the development of the direct oxidation method, the production of ethylene oxide has increased so significantly that today it is one of the largest volume products of the chemicals industry, accounting, by some estimates, for as much as half of the total value of organic chemicals produced by heterogeneous oxidation.
Given the foregoing there is a continuing need in the art to optimize the formulation and usage of ethylene oxide catalysts, especially across the range of temperatures, reaction conditions, and reactor feed compositions that they are subjected to in current commercial ethylene oxide reactor units.